1857年,德国统计学家恩格尔根据统计资料,对消费结构的变化得出一个定律:一个家庭,其收入越少,家庭收入中(或总支出中)用来购买食物的支出所占的比例就越大,随着家庭收入的增加,家庭收入中(或总支出中)用来购买食物的支出比例则会下降。推而广之,一个国家越穷,每个国民的平均收 In 1857, according to statistical data, Engel, a German statistician, came to the conclusion that the change in the structure of consumption leads to a law: the proportion of expenditures that a household earns less, the share of household income (or total expenditure) spent on food purchases is The larger the proportion of household income (or total spending) spent on food purchases declines as household income increases. By extension, the poorer a country is, the average income per citizen